Relative dating ppt

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These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in the matrix.

As a result, xenoliths are older than the rock which contains them.

The regular order of the occurrence of fossils in rock layers was discovered around 1800 by William Smith.

Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault.

Photo from Glen Canyon National Recreation Area, Utah.

Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another.

For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer.

A similar situation with igneous rocks occurs when xenoliths are found.